{"id":7753,"date":"2020-09-20T17:17:03","date_gmt":"2020-09-20T14:17:03","guid":{"rendered":"http:\/\/blog.ulubat.org\/?p=7753"},"modified":"2020-09-20T17:17:05","modified_gmt":"2020-09-20T14:17:05","slug":"hafizanin-uzerindeki-sis-perdesini-kaldiran-olay-henry-molaison-vakasi","status":"publish","type":"post","link":"https:\/\/blog.ulubat.org\/index.php\/genel\/hafizanin-uzerindeki-sis-perdesini-kaldiran-olay-henry-molaison-vakasi\/","title":{"rendered":"Haf\u0131zan\u0131n \u00dczerindeki Sis Perdesini Kald\u0131ran Olay: Henry Molaison Vakas\u0131"},"content":{"rendered":"\n

“Bana \u015fu anki\nABD ba\u015fkan\u0131n kim oldu\u011funu s\u00f6yler misiniz?”<\/em><\/p>\n\n\n\n

 <\/em>1986’da Massachusetts\nInstitute of Technology<\/em>‘de bir ofiste, 60 ya\u015f\u0131na yakla\u015fm\u0131\u015f bir erkek hasta ile bir n\u00f6ropsikolog\noturuyorlard\u0131. <\/p>\n\n\n\n

“Hay\u0131r.” <\/em>dedi, “Hat\u0131rlayam\u0131yorum.” <\/em><\/p>\n\n\n\n

 “En son hat\u0131rlad\u0131\u011f\u0131n\u0131z\nba\u015fkan\u0131n kim oldu\u011funu s\u00f6yleyebilir misiniz?”<\/em> Biraz duraksama ve\n\u00fczerine d\u00fc\u015f\u00fcnmenin ard\u0131ndan “Ike”\n<\/em>yan\u0131t\u0131n\u0131 verdi. Ike, 1953-1960 y\u0131llar\u0131 aras\u0131nda ba\u015fkanl\u0131k yapan Dwight\nDavid Eisenhower’\u0131n lakab\u0131yd\u0131. Ancak tarihler 1986 y\u0131l\u0131n\u0131 g\u00f6steriyordu ve onun\nba\u015fkanl\u0131\u011f\u0131 \u00fczerinden neredeyse 33 y\u0131l ge\u00e7mi\u015fti. <\/p>\n\n\n\n

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Heny Molaison – wikimedia<\/figcaption><\/figure><\/div>\n\n\n\n

1930’lu y\u0131llar\u0131n\nba\u015f\u0131nda Henry Molaison, 7 ya\u015f\u0131ndayken ge\u00e7irdi\u011fi bir bisiklet kazas\u0131ndan birka\u00e7\nsene sonra, ya\u015fad\u0131\u011f\u0131 kafa travmas\u0131 nedeniyle geli\u015fti\u011fi d\u00fc\u015f\u00fcn\u00fclen min\u00f6r\nepileptik n\u00f6betler ya\u015famaya ba\u015flad\u0131. Ya\u015f\u0131 ilerledik\u00e7e ge\u00e7irdi\u011fi n\u00f6betler\ns\u0131kla\u015ft\u0131 ve gittik\u00e7e \u015fiddeti artt\u0131. 1953’te H.M. 27 ya\u015f\u0131na geldi\u011finde n\u00f6betlerin\n\u015fiddetinden dolay\u0131 hayat\u0131n\u0131 devam ettiremez hale geldi. Kulland\u0131\u011f\u0131 y\u00fcksek dozda\nantikonv\u00fclzanlar dahi, art\u0131k onu normal ya\u015fama d\u00f6nd\u00fcrmeye yetmemeye ba\u015flad\u0131.<\/p>\n\n\n\n

N\u00f6betlerin\ndayan\u0131lmaz hale gelmesinin ard\u0131ndan, 1953 y\u0131l\u0131n\u0131n Mart ay\u0131nda Hartford\nHastanesinde beyin cerrah\u0131 olan ve yapt\u0131\u011f\u0131 lobotomi ameliyatlar\u0131yla ABD’de\nhatr\u0131 say\u0131l\u0131r bir \u00fcne sahip olan Dr. William Beecher Scoville, H.M.’ye  deneysel bir operasyon \u00f6nerdi. Bu operasyonda\nbeyninin her iki taraf\u0131ndan par\u00e7a \u00e7\u0131kar\u0131lacak ve b\u00f6ylece H.M.’nin epilepsisi tedavi\nedilmi\u015f olacakt\u0131. <\/p>\n\n\n\n

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H.M.’nin lobotomisinin modeli – nytimes<\/figcaption><\/figure>\n\n\n\n

Dr. Scoville,\nlobotomi konusunda \u00e7ok tecr\u00fcbeli olmas\u0131na ra\u011fmen 1950’li y\u0131llar\u0131n teknolojik\nimkanlar\u0131n yetersizli\u011fi nedeniyle epilepsi oda\u011f\u0131n\u0131 net olarak saptamak\nimkans\u0131zd\u0131. Baz\u0131 vakalarda epilepsi normal \ng\u00f6z\u00fcken beyin b\u00f6lgelerinden bile kaynaklanabiliyordu. Dolay\u0131s\u0131yla bu\noperasyon fazlas\u0131yla deneysel bir operasyon olacakt\u0131. Bu bilinmezli\u011fe ra\u011fmen\nH.M.’nin n\u00f6betlerinin ortadan kalkma ihtimali ailesi taraf\u0131ndan de\u011ferlendirilerek\noperasyona izin verildi.<\/p>\n\n\n\n

O d\u00f6nemin\nteknolojik imkanlar\u0131 Dr.Scoville’in H.M.’nin epilepsi oda\u011f\u0131n\u0131 net olarak\nbelirleyebilmesine yetmiyordu. Dolay\u0131s\u0131yla Scoville’in yapaca\u011f\u0131 operasyon ciddi\nmanada deneysel ve i\u00e7g\u00fcd\u00fcsel bir i\u015flem olacakt\u0131. O d\u00f6nemde sinirbilim ad\u0131na\nat\u0131lan ciddi ad\u0131mlar\u0131n b\u00fcy\u00fck bir k\u0131sm\u0131 rastgele at\u0131l\u0131yordu. Scoville hastan\u0131n\nmedial temporal lobunu \u00e7\u0131karmay\u0131 planlad\u0131. O d\u00f6nemde medial temporal lobun\nhipokamp\u00fcs, amigdala, parahipokampal gir\u00fcs, dentat gir\u00fcs ve uncus par\u00e7alar\u0131n\u0131 i\u00e7erdi\u011fi\nbiliniyor; fakat bu b\u00f6lgelerin ne i\u015fe yarad\u0131\u011f\u0131 bilinmiyordu.<\/p>\n\n\n\n

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Medial Temporal Lob – American Journal of Neuroradiology<\/figcaption><\/figure><\/div>\n\n\n\n

Operasyondan\n\u00f6nce H.M. rutin kan testleri, EEG ve bir tak\u0131m psikiyatrik testlerden ge\u00e7ti ve\nlobotomi ameliyat\u0131n\u0131n yap\u0131lmas\u0131nda herhangi bir sak\u0131nca g\u00f6r\u00fclmedi. 25 A\u011fustos\n1953 g\u00fcn\u00fc Dr.Scoville planlad\u0131\u011f\u0131 gibi medial temporal loblar\u0131n her ikisini de\nbeyinden ba\u015far\u0131yla \u00e7\u0131kard\u0131 ve bilim tarihine ge\u00e7ecek operasyon tamamlanm\u0131\u015f\noldu.<\/p>\n\n\n\n

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H.M.’nin operasyon sonras\u0131 beyni ile normal beyin kar\u015f\u0131la\u015ft\u0131rmas\u0131<\/figcaption><\/figure><\/div>\n\n\n\n

Ameliyat\u0131n ard\u0131ndan\nH.M.’nin \u015fikayetleri b\u00fcy\u00fck \u00f6l\u00e7\u00fcde giderildi \nve hayat kalitesi y\u00fckselmeye ba\u015flad\u0131; ancak birka\u00e7 ay sonra bu iyi\ngeli\u015fmelere ra\u011fmen yolunda gitmeyen ciddi bir \u015feyler g\u00f6zlenmeye ba\u015flad\u0131: H.M.\nameliyattan sonras\u0131na dair hi\u00e7bir an\u0131 olu\u015fturam\u0131yordu. H.M.’nin \u015fimdilik alg\u0131s\u0131\ntamamen bozulmu\u015f ve yeni olu\u015fturdu\u011fu an\u0131lar\u0131 birka\u00e7 dakikadan daha uzun\nhaf\u0131zas\u0131nda tutamaz olmu\u015ftu. H.M.’nin ki\u015fili\u011finde, entellekt\u00fcel kapasitesinde,\nIQ’s\u00fcnde herhangi bir kay\u0131p olmamas\u0131na ra\u011fmen haf\u0131zas\u0131 \u00e7ok ciddi bir zarar\ng\u00f6rm\u00fc\u015ft\u00fc.<\/p>\n\n\n\n

H.M.’nin\noperasyonun ard\u0131ndan bilim adamlar\u0131n\u0131n o g\u00fcne kadar haf\u0131zan\u0131n beynin tamam\u0131na\nyay\u0131lm\u0131\u015f \u015fekilde olu\u015ftu\u011funa inanc\u0131n\u0131n yanl\u0131\u015f oldu\u011fu kan\u0131tlanm\u0131\u015f oldu. B\u00f6ylece\nbellek art\u0131k somut bir b\u00f6lmede g\u00f6sterilebilir olmu\u015ftu. Hippokamp\u00fcs’\u00fcn insan\nzihninde neye kar\u015f\u0131l\u0131k geldi\u011fi anla\u015f\u0131lmas\u0131n\u0131n ard\u0131ndan n\u00f6robilimde haf\u0131zaya\ndair ara\u015ft\u0131rmalar derinle\u015ftirildi.<\/p>\n\n\n\n

H.M.’nin\nayd\u0131nlanmas\u0131na \u00f6nc\u00fcl\u00fck etti\u011fi haf\u0131za konusunda derinle\u015ftirilen ara\u015ft\u0131rmalar\nneticesinde belle\u011fin uzun ve k\u0131sa bellek olarak ikiye ayr\u0131ld\u0131\u011f\u0131 anla\u015f\u0131ld\u0131.\n\u00c7\u00fcnk\u00fc, H.M. haf\u0131zas\u0131n\u0131 sadece birka\u00e7 dakika doldurabiliyordu. B\u00f6ylece k\u0131sa ve\nuzun bellek somut olarak tan\u0131mlanm\u0131\u015f ve zaman olarak kar\u015f\u0131l\u0131klar\u0131\nnetle\u015ftirilmi\u015f oluyordu. <\/p>\n\n\n\n

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Haf\u0131za T\u00fcrleri \u015eemas\u0131 – pscychestudy<\/figcaption><\/figure><\/div>\n\n\n\n

Belle\u011fin zamansal\nolarak k\u0131sa ve uzun bellek olarak ayr\u0131lmas\u0131n\u0131n yan\u0131nda bi\u00e7imsel olarak da\nayr\u0131labilece\u011fi de H.M. vakas\u0131 neticesinde ke\u015ffedilmi\u015f oldu. Belle\u011fin uzun\ns\u00fcreli bellek ve k\u0131sa s\u00fcreli bellek yan\u0131nda 3 \u00f6nemli par\u00e7as\u0131 daha mevcuttur: An\u0131sal bellek, anlamsal bellek, i\u015flemsel\nbellek. <\/em>An\u0131sal bellek, ki\u015finin kendi hayat\u0131na dair do\u011fumundan itibaren\nya\u015fad\u0131klar\u0131 \u00f6rne\u011fin kimin \u00e7ocu\u011fu oldu\u011fu, nerede do\u011fup b\u00fcy\u00fcd\u00fc\u011f\u00fc, hangi okullara\ngitti\u011fi gibi parametrelerini i\u00e7eren bellektir. Anlamsal bellek ise hemen hemen\nherkesin a\u015fina oldu\u011fu genel ge\u00e7er do\u011frular\u0131 ki\u015finin ya\u015fad\u0131\u011f\u0131 d\u00f6nemi\nilgilendiren bilgileri i\u00e7eren bellektir. \u0130\u015flemsel bellek ise psikomotor\neylemleri \u00f6rne\u011fin, bisiklet s\u00fcrmeyi \u00f6\u011frenmek gibi bilgileri i\u00e7eren bellek\nt\u00fcr\u00fcd\u00fcr. H.M. ameliyattan sonra kendi ge\u00e7mi\u015fine dair bilgileri hat\u0131rlamakta\ng\u00fc\u00e7l\u00fck \u00e7ekerken ameliyat \u00f6ncesine dair toplumsal bilgileri \u00f6rne\u011fin, o d\u00f6nemki\ndevlet ba\u015fkan\u0131n\u0131n ad\u0131n\u0131 hat\u0131rl\u0131yordu. Bundan hareketle, H.M.’nin beyninden\n\u00e7\u0131kar\u0131lan b\u00f6lgenin an\u0131sal belle\u011fi kontrol etti\u011fi anla\u015f\u0131lm\u0131\u015f oldu. H.M.\noperasyondan sonra yeni aletleri \u00f6rne\u011fin, koltuk de\u011fne\u011fi kullanmay\u0131 bir daha\n\u00f6\u011frenmesine gerek kalmayacak \u015fekilde kal\u0131c\u0131 bi\u00e7imde \u00f6\u011frenebilmi\u015fti. Hatta H.M.\nbir \u00e7akmak fabrikas\u0131nda \u00e7akmaklar\u0131 kartona yerle\u015ftirmeyi \u00f6\u011frenerek bir i\u015fe de\ngirebildi. B\u00f6ylece i\u015flemsel belle\u011fin de konumuna dair bilgiler elde edilmeye\nba\u015fland\u0131.<\/p>\n\n\n\n

H.M. vakas\u0131\nn\u00f6robilimin haf\u0131za konusunda kat etti\u011fi yolda \u00e7ok \u00f6nemli bir d\u00f6n\u00fcm noktas\u0131\nolmu\u015ftu. Sinirbilim ve n\u00f6ropsikoloji alan\u0131nda i\u015flevsel beyin anatomisi ve\nhaf\u0131za ile ilgili geli\u015fmeler bu vakaya at\u0131flarda bulunularak anlat\u0131l\u0131yordu.<\/p>\n\n\n\n

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Henry Gustav Molaison – theguardian<\/figcaption><\/figure><\/div>\n\n\n\n

H.M. \u00f6l\u00fcm\u00fcne kadar\nkendini 27 ya\u015f\u0131nda sand\u0131, aynaya her bak\u0131\u015f\u0131nda g\u00f6rd\u00fc\u011f\u00fc ya\u015flanm\u0131\u015f y\u00fcz kar\u015f\u0131s\u0131nda\n\u015fa\u015f\u0131rd\u0131. Ameliyat\u0131ndan 2 Aral\u0131k 2008 tarihindeki \u00f6l\u00fcm\u00fcne kadar ya\u015fad\u0131klar\u0131n\u0131n\nhi\u00e7birini hat\u0131rlayamad\u0131 ve sinirbilim tarihinin d\u00f6n\u00fcm noktalar\u0131ndan birini\nolu\u015fturdu\u011funu da hi\u00e7bir zaman fark edememi\u015f oldu. 1953 y\u0131l\u0131ndan 2008 y\u0131l\u0131ndaki\n\u00f6l\u00fcm\u00fcne kadar 55 y\u0131ll\u0131k s\u00fcrede, n\u00f6robilim tarihinin en \u00f6nemli sis perdelerinden\nbirinin ayd\u0131nlanmas\u0131n\u0131 sa\u011flayan hastan\u0131n ad\u0131 \u00f6l\u00fcm\u00fcnden sonra Henry Molaison\nolarak a\u00e7\u0131kland\u0131.<\/p>\n\n\n\n

KAYNAK\u00c7A:<\/h2>\n\n\n\n